Method for manufacturing tubes with enlarged ends



Sept. 10, 1929. H. A. STAPLES 1,723,016

METHOD FUR MANUFACTURING TUBES WITH ENLARGED ENDS Filed June 9, 1926 INVENTOR HOW/165A. STAPLES.

ATTORNEY Patented Se t. 10, 1929.

UNITED STATES PATENT OFFICE.

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Application filed June 9, 1926. Serial No. 114,?89.

My invention relates to a method of producing tubes with enlarged ends, or ends of .special shape, more particularly to tubes for condensers that require a tube of two diameters and has for its object the production of such a tube with a connecting neck between the two diameters that is in cross section a reverse curve the radii of the curve being tangentially connected.

A further object is to produce a tube of uniform wall thickness substantially throughout its length no matter how the diameter changes.

The-foregoing and other features of my invention will now be described in connection with the accompanying drawing forming part of this specification in which I have diagrammatically illustrated the various steps of my process as I prefer to practiceit, after which I shall point out in the claims those features which I believe to be new and of m own invention.

Figure 1 illustrates the product as produced by my process showing the reverse curve to the neck.

Figure 2 illustrates the forming mandrel and drawing mandrel used for the particular shape tube illustrated in Fig. 3;.

Figure 3 diagrammatically illustrates the drawing of the tube through a fixed die.

Figure 4 diagrammatically illustrates how the radius R of the reversed curve is formed in the tube, the last step in the process.

In the carrying out of my process 1 employ any standard apparatus used in drawing mills such as draw benches or presses, and as these are in common use and familiar to those skilled in the art they require no description herein. Two such draw benches or presses are required and are placed end to end so that they may operate in opposite directions.

My process will produce the tube shown in Figu' e 1 with the long shank 10, enlarged end 11, and the adjoining neck portion 12. llhe neck portion is formed so that the longitudinal section will take the shape of a gradually varying reverse curve with substantially the same wall thickness throughout. It will be observed that the section lar reverse curved section that is the diameter of end 11 if desire The tube with the mandrels inserted is put in either a. draw bench or' press and drawn through a iixed die 30 by pulling in one direction as shown in Figure 3. The

other-draw bench or press is then utilized to withdraw the drawing mandrel by pulling in the opposite direction which shapes the curved portion of the reverse neck 12 or the radius R of the sect-ion by reason of the force exerted on the tube due to friction between the drawing'mandrel and the inside of the tube just drawn.

I wish it distinctly understood that my method for manufacturing tubes with enlarged ends herein described and. illustrated is in the form in which I desire to practice it and that changes or variations may be made as may be convenient or desirable without departing from the salient features of my invention and I therefore intend the following claims to cover such modifications as naturally fall within the lines of invention.

I claim:

1. A method of manufacturing tubes of diflerent diameters, comprising the steps of drawing a tube part way of its length over an arbor forming that portion of the tube of small diameter, and a connecting portion of abrupt outline, holding the enlarged end and withdrawing the arbor through the enlarged end the friction between the small end and the arbor being momentarily suflicient to move the small end toward the large 7 end to change the outline between the ame from an abru t to an ogee form.

2. A metho of manufacturing tubes with I enlarged ends comprising the steps of placing the tube over a. forming mandrel through which freel slides a drawing mandrel, drawing the tn 8 and drawing mandrel through a die by pulling in one direction, withdrawing the drawing mandrel at the same time supporting the forming mandrel by pulling the drawing mandrel in the opposite direction whereby theenlarged end of tllie tube is formed into the desired ogee s ape.

In testimony whereof I aflix my signature.

HORACE A. STAPLES. 

